Christmas trees require a number of trimmings during their lifetime prior to being harvested for sale to the general public. Typically, they are trimmed a number of times per year. A number of devices have been developed for automatically shaping the trees. These are represented in U.S. Pat. No. 3,496,709, issued to L. E. Ebert on Feb. 24, 1970, U.S. Pat. No. 3,888,071, issued to L. E. Wallace on June 10, 1975 and U.S. Pat. No. 4,383,401, issued to K. R. Lessard, et al. on May 17, 1983.
The Ebert device illustrates a side mounted Christmas tree shaper which comprises a boom for holding a trimming apparatus. The trimming apparatus is comprised of a horizontal bar which is rotatable through 360.degree.. The rotatable bar has a member reciprocated thereon and parallel to the ground. Attached to this member is a cutter mechanism which can be disposed at an angle with respect thereto. This cutter mechanism can be reciprocated along the horizontal plane of the rotating bar such that it defines a conical cutting surface coaxial with the rotating axis of the bar. This device has a disadvantage in that it is side mounted and must be attached to a vehicle that is of such dimensions to travel between rows of Christmas trees.
The Wallace device utilizes a rotating platform through which a cutter mechanism is disposed at a variable length downward therefrom. The platform is adjustable in height and is operable to straddle the Christmas tree.
The Lessard device discloses a rotating cutter which is mounted on a boom on the front of a tractor. The boom is swung out over the tree while the tractor or mobile platform moves between the rows. Once the boom is raised over the tree, it is necessary to level the cutting apparatus such that it defines a cone shape. This requires two hydraulic cylinders to adjust the level thereof to define the correct conical shape for the tree. A disadvantage to this device is lining up the cutting member with respect to the desired cone shape for the tree.
The above devices having a number of disadvantages in that the Lessard and Ebert device are side mounted and are difficult to align to provide the correct conical shape and the Wallace device is cumbersome in that it must raise the entire device above the level of the trees to provide the cutting operation. Therefore, in view of the above disadvantages, there is a need for an improved trimming apparatus.